Year 8 Biology: Food Web

What is a Food Web?

A food web is a way to show how different living things in an ecosystem are connected through what they eat. It shows how energy and nutrients flow from one organism to another.

Key Terms:

• Producer: These are plants that make their own food using sunlight. For example, grass or trees.
• Consumer: These are animals that eat plants or other animals.
  • Herbivores eat plants (like rabbits).
  • Carnivores eat other animals (like lions).
  • Omnivores eat both plants and animals (like humans).
• Decomposer: These are organisms that break down dead plants and animals, returning nutrients to the soil. Examples include fungi and bacteria.

How Does a Food Web Work?

1. Energy Flow: The sun provides energy to plants (producers). When animals eat plants, they get energy from them.
2. Connections: Animals can be linked in many ways. For example, a rabbit eats grass, and then a fox might eat the rabbit. This creates a network of connections, which is our food web.
3. Complexity: A food web is more complex than a food chain. A food chain shows a simple path of energy flow (e.g., grass → rabbit → fox), but a food web shows many paths (e.g., grass → rabbit, grass → deer, rabbit → fox, deer → wolf).

Examples of a Food Web

Imagine a small forest ecosystem:

• Producers: Grass, bushes, and trees.
• Consumers: Rabbits (herbivores), deer (herbivores), foxes (carnivores), and hawks (carnivores).
• Decomposers: Fungi and bacteria that break down dead plants and animals.

Here’s how it connects:

• Grass is eaten by rabbits and deer.
• Rabbits are eaten by foxes.
• Deer can be hunted by hawks or wolves.

Key Rules for Understanding Food Webs:

1. Start with Producers: Always identify the plants first. They form the base of the food web.
2. Follow the Arrows: In diagrams, arrows show the direction of energy flow. The arrow points from the food source to the consumer.
3. Look for Interconnections: Notice how different consumers can eat the same producers or how they might compete with each other.
4. Think About Decomposers: Remember that when plants and animals die, decomposers play an important role in recycling nutrients back into the soil.

Tips and Tricks

• Draw It Out: Create your own food web using animals and plants from your local area or favourite ecosystem.
• Use Colour Coding: Use different colours for producers, consumers, and decomposers to make it easy to understand.
• Think About Changes: What happens if one species disappears? Discuss how it affects others in the web.

Questions About Food Webs

Easy Level Questions

1. What is a producer?
2. Name one herbivore.
3. What do carnivores eat?
4. Give an example of an omnivore.
5. What role do decomposers play in a food web?
6. What do plants use to make food?
7. Name one animal that is a producer.
8. What do rabbits eat?
9. Who eats the rabbit?
10. What connects all living things in a food web?
11. What is the process called where plants make their own food?
12. What type of animal is a fox?
13. Can a food web have more than one producer? (Yes/No)
14. What do fungi break down?
15. What is the main source of energy for plants?
16. Do all animals eat the same food? (Yes/No)
17. What happens to energy as it moves up the food web?
18. Can a plant be eaten by more than one animal? (Yes/No)
19. What is an example of a herbivore?
20. Who is at the top of a food web?

Medium Level Questions

1. Explain the difference between a food chain and a food web.
2. Why are producers important in a food web?
3. How do herbivores get energy?
4. What might happen if all the rabbits died?
5. Describe the role of decomposers in an ecosystem.
6. Can a carnivore also be an omnivore? Give an example.
7. What happens to energy when a predator eats its prey?
8. How does energy flow through a food web?
9. Identify a food web in your local area.
10. Why might a food web be disrupted?
11. Name two animals that are both consumers.
12. What do plants need besides sunlight to grow?
13. How are food webs affected by seasonal changes?
14. Why is it important to have a variety of species in a food web?
15. What is an apex predator?
16. What role does sunlight play in a food web?
17. How can human activities affect food webs?
18. What would happen to the food web if all the plants died?
19. Describe how a hawk and a fox might compete.
20. How do decomposers help plants grow?

Hard Level Questions

1. Explain how energy is lost at each level of a food web.
2. What is the significance of biodiversity in a food web?
3. Describe an example of a food web in a marine ecosystem.
4. How do invasive species impact food webs?
5. Discuss how climate change affects food webs.
6. Why is it important to study food webs in environmental science?
7. Explain the concept of trophic levels in a food web.
8. How do food webs illustrate the concept of interdependence?
9. What would happen if a top predator was removed from a food web?
10. Discuss the relationship between herbivores and producers.
11. Describe what is meant by a “keystone species.”
12. Explain how energy pyramids relate to food webs.
13. How does nutrient cycling occur in a food web?
14. What are some human impacts on local food webs?
15. Why do decomposers matter to the health of an ecosystem?
16. How can changes in one species affect others in a food web?
17. Compare and contrast a terrestrial food web with an aquatic food web.
18. What role do scavengers play in a food web?
19. How do food webs help in understanding ecological balance?
20. Discuss the importance of studying food webs for conservation efforts.

Answers to Questions

Easy Level Answers

1. A producer is a plant that makes its own food.
2. A rabbit.
3. Carnivores eat other animals.
4. Humans.
5. They break down dead plants and animals.
6. Sunlight.
7. No animals are producers; only plants are.
8. Rabbits eat grass.
9. Foxes eat the rabbit.
10. They show energy flow.
11. Photosynthesis.
12. A carnivore.
13. Yes.
14. Dead matter.
15. Sunlight is the main energy source.
16. No.
17. Energy decreases.
18. Yes.
19. A cow.
20. The top of a food web is often occupied by predators.

Medium Level Answers

1. A food chain shows a simple path, while a food web shows many paths.
2. They are the starting point for energy.
3. Herbivores get energy by eating plants.
4. Other animals might overpopulate.
5. They recycle nutrients back into the soil.
6. Yes, bears are omnivores.
7. Energy is transformed into growth.
8. Energy flows from producers to consumers.
9. A food web in your area might include local plants and animals.
10. It can lead to imbalances.
11. A rabbit and a deer.
12. Water and nutrients.
13. Seasonal changes can affect food availability.
14. It helps maintain ecosystem balance.
15. An apex predator is a top predator with no natural enemies.
16. Sunlight is essential for photosynthesis.
17. They can disrupt food availability.
18. The animals would have no food.
19. They may compete for the same prey.
20. Decomposers return nutrients to the soil.

Hard Level Answers

1. Energy is lost as heat and waste.
2. Biodiversity keeps ecosystems stable.
3. An example is a coral reef food web.
4. They can outcompete native species.
5. It can alter species populations.
6. Understanding food webs helps us to manage ecosystems.
7. Trophic levels show the position of organisms in a food web.
8. Organisms depend on each other for food and survival.
9. It can lead to overpopulation of prey species.
10. Herbivores rely on producers for food.
11. A keystone species is crucial for the ecosystem’s structure.
12. Energy pyramids show energy flow and loss at trophic levels.
13. Nutrient cycling happens through decomposition.
14. Pollution and habitat destruction can harm food webs.
15. They keep the ecosystem healthy.
16. Changes can disrupt the balance of the ecosystem.
17. Terrestrial food webs include land plants and animals; aquatic webs include water organisms.
18. Scavengers clean up dead matter.
19. They illustrate the balance of nature.
20. Conservation efforts rely on understanding species interactions.

Feel free to use this guide to understand food webs better and answer the questions to test your knowledge!